Cellular adhesion mechanisms have been recognized as crucial elements regulating the targeting of individual cells to their sites of function. Adhesion determinants direct such critical features as the migration of normal and abnormal skin components in growth and wound healing, the metastatic properties of tumor cells and as the accumulation of leukocytes in the response to infection and the development of inflammatory diseases. As such, investigation of cell adhesion properties is central to the study of skin pathophysiology. The Leukocyte Adhesion Core was developed to provide HSDRC investigators with ready access to high quality assays of human and murine leukocyte adhesion and migration and expert assistance with the design and execution of these assays. The strong interest in Leukocyte Migration Core resources over the past five years has reinforced our belief that the research of many established and new skin disease research scientists is aided significantly by a technical and intellectual center that can assist in the planning and execution of cell migration and adhesion experiments. The considerable expense and the setup and training time necessary to generate high quality assays of human and murine leukocyte adhesion and migration represents a barrier to entry for many investigators.The specialized in vitro and in vivo techniques and extensive experience of the Core Directors will continue to serve as the basis for the value this of this Core to SDRC investigators. Through the implementation of new technologies, including novel in vitro flow assays and multi-photon confocal intravital microscopy, along with expanded access to more conventional adhesion and migration assay techniques, the Core will continue to provide users with access to cutting edge technology for application to their research questions. In addition, mice engineered by Dr. von Andrian to express fluorescent proteins in T cells and/or specific T cell subpopulations, have been produced and characterized and are now available to HSDRC investigators. Services provided by the Leukocyte Migration Core are divisible into support for in vitro binding studies, in vivo homing model systems and intravital epifluorescence and multi-photon microscopy techniques. Although considerable overlap and collaboration exists, Dr. Fuhlbrigge will continue to provide primary support for in vitro core services at the Harvard Institutes of Medicine and Dr. von Andrian will provide primary support for intravital microscopy core services at the Center for Blood Research. Whole animal in vivo homing studies will continue to be supported in both facilities.